I couldnt tell you for sure about the clearance but with all the room in the wheel wells on my '90 3/4 ton I wouldnt imagine you having a problem. Those tires are 30.5" tall and the new ones would be 33.1" tall...thats an extra 1-1/4" in either direction from center and the width change would be minimal. In fact Tirerack.com considers the 255/85 a "plus zero" tire which means it is a little wider than stock (235/85) but about the same diameter.

How cheap? I bought a set of take offs from a late model Tahoe, wheels, tires, lugs, and center caps for $400. See the post. There are some sweet deals out there for wheels and tires on craigslist. With the 20" and bigger wheel craze you can buy a set of take offs pretty cheaply and if you don't want the wheels, post 'em here or back on craigslist.

I run 285/75 x16's on my Subs and have minimal clearence issues with stock suspension. With the early bodystyle you should be fine, I think the 255/85x16 is very close in diameter to the 285/75's.:glasses: